THE ACTION OF ORGANIC A N D MINERAL ACIDS UPON SOILS. \',I
11 l I < I < \
5s\
111
K
18i)i
I
K soil analysis. the i i y d r (
cid use for dissolving the potash, linie. aut1 plir~spliateshas a specific gravity of I . I 1 5 . This acid is used because it is supposed to represent, practically, the same solvent power which agricultural plaiits possess in obtaining their fOCJd from the soil. Iiiasiiiuch as this premises is tlie foundation of a part ol t ~ i epresent system of soil anilysis, it is a questioii of the greatest importance. One of the indicatioils which pixits to the truth of the preniises is the similarity of tlic action of h y d r o c h h i c w i d ( J f this strength, and of organic acids upon saniplcs of w i l . ( ) ~ 4 7 c z ~,-lc~'ds. ir ----I11wiiie of the soil work which has been in prog-ress i n the clieiiiical lalioratoi-y of the Minnesota Experiinelit Stntiori, tlic solveiit action of the various organic acids has been deteriiiinccl Tvitli another ultiiiiate object i n viex. Incidelitall>.,the results give sufficient data for the comparative acid, sp. g r . , I . I 1 5 , nctioii of tlieorgaiiicacids and of h~~tlrocliloric UiXJn the same saniples of soil. Different types of soil arc acted upon quite differently by the various organic acids, and getieral coriclusions regarding their action u p i i vari(.)us t ) p s of soil can not be stated. Hence the stateiiicnts which are made upon this question have reference old!, to the tj-pe of soil under consideratioa. T h e figures given i i i the table were obtained from a soil saiiiple taken from one of the rotation plots at the Experiment Station. 1x1obtaiiiing tlic solutions for analJ-sis, oxalic, tartaric, of ten per cent. strength, by weight, were used. T h e digestioii was carried on for thirty-six hours in the S n j d e r soil flask as used at this station. T h e organic acid iiiixture was inade by preparing a ten per cent. solution, by weight of citric, oxalic, and tartaric acids. The material soluble in the organic acids n-as separated by filtration and washing. The solution was then gently ignited to remove the organic acids, so that the analysis could be completed in the usual way.
ACTION O F O R G A N I C AND MINERAL ACIDS UPON SOILS.
149
Ten per cent. solutions were used because the more concentrated ones crystallized upon standing, and, then too, preliminary trials indicated that the more concentrated organic acid solutions possessed less solvent power than those here used. One difficulty experienced in the work was obtaining tartaric acid free from potash, and citric and oxalic acids free from lime. All of the determinations were made in duplicate, and controlled by blank determinations.
TABLEI. SOLVENT ACTIONOF HYDROCHLORIC A N D ORGANIC ACIDS UPON
A
Sort.
Ten per cent. solution of Hydrochloric acid 1.115 sp. gr.
Total insoluble, per cent.. .. Potash Soda Lime.. Magnesia Iron oxide .................. Alunlina Phosphoric anhydride.. Sulphuric
...................... ........................ ...................... ................... .................... ..... .........
84.08 0.30 0.25
0.51 0.26 2.56 4.24 0.23 0.08
7
---'--
citric acid.
oxalic acid.
87.90 85.07
tartaric orgniiic acid acid. mixture.
0.12
0.18
87.67 0.06
0.17 0.50 0.27 1.59 1.45 0.26
0.19
0.05
0.12
0.23
0.41
0.45
0.21 1.14
0.32 1.62 1.77
0.14
0.11
0.33 2.23 2.99 0.26
0.10
0.05
0.06
0.05
3.96
85.93 0.10
T h e oxalic acid caused an increase in the solubility of the alumina. There is a marked difference between the solvent action of these three acids. T h e oxalic acid possesses the greatest solvent action upon the complex insoluble matter of an alkaline nature. T h e citric acid possesses the greatest solvent action upon the lime, magnesia, and the sulphuric and phosphoric anhydrides. T h e amount of lime dissolved by the oxalic acid is greater than would, a t first, be expected, but the complex nature of the solution, and the presence of the salts of other metals, has caused nearly half as much lime to be dissolved by the oxalic acid as by the hydrochloric acid'of sp. gr. 1.1 1 5 . T h e ten per cent. mixture of the three organic acids has resulted in dissolving as much phosphates and magnesia, and nearly as much lime as any one of the acids acting alone. T h e potash does not appear to be as soluble in the organic acid mixture as the other elements of plant food. T h e amount of potassiuni, iron, and aluminum oxides, dissolved by these three organic acids and their mixtures is somewhat less than that dissolved by the hydrochloric acid. T h e
I50
A C T I O N O F O R G A N I C A N D MINERrlI. .4CIDS UPON SOILS.
iron and aluniina are not of any econoniic importance in interpreting the results of soil analysis. The main difference between the solvent action of the hydrochloric and the organic acids is in the somewhat smaller amount of potash dissolved by the organic acids. IVith the exception of the solubility of the potash, as noted, these results bring out, in a general manner, the value of hydrochloric acid of I . I 15 sp. gr. as a solvent, over the organic acids, of ten per cent. streiigth, because the hydrochloric acid represents the limit of the solvent action reached by any one of the organic acids acting alone or in a mixture. For the purpose oi coniparison, the solvent action of hydrochloric acid, sp. gr. I . I I j , and the niaxiniuni liiiiit reached in ally case, by the organic acids, are given, together with the iianie of the acid possessing the highest solvent power for that constituent. TABLE11. I.ar e s t amount $issolved Hydrochloric acid, 5p. g r . 1.115. by organic acids.
Total insoluble, per ceut.. ...... 84.08 Potash. ......................... 0.30 Sotla. ........................... 0.25 Lime...'. ........................ 0.51 Magnesia ....................... 0.26 Iron oxide.. ..................... 2. j6 Alumina ........................ 4.24 Phosphoric anhydride.. ......... 0.23 Sulphuric *' ........... 0.0s
8j.07 0. I 8
0.19 0.50
0.27 2.23
3.96 0.26 0. I O
Name of the o y n n i c acd
Oxalic Oxalic Oxalic Citric Citric Mixture Oxalic r Citric and 'L Mixture Citric
A T f w m Acids. ~ -The :rction of tile coriceritrated iiiiricral acids upoii the same sample of soil is giveri in Table 111. Concentrated hydrochloric acid, forty per cent. strength, dissolved two and a quarter per ceiit. niore of the coniplex silicates than nitric acid of the sanie strength. Concentrated nitric acid possesses a stronger solvent action than the dilute hydrochloric acid. T h e coiicentrated hydrochloric acid dissolved somewhat niore potash thaii the hydrochloric acid of I .I I j sp. gr. T h e amount of lime, phosphates, and sulphates, dissolved by the concentrated hydrochloric acid, was about the same as when the more dilute acid was used ; the concentrated acid, however, dissolved more of the coinplex silicates of potash, iron, and alumina. Sulpliuric acid possesses the strongest solvent action.
NEW BOOKS.
151
Of the total potash in the soil, as determined by fusion, less than eighteen per cent. is soluble in the hydrochloric acid as used in soil analysis; about ten per cent. is soluble in oxalic acid, and three per cent. in tartaric acid. TABLE 111. CONCENTRATED ACIDS. Hydrochloric acid.
......
Total insoluble, per cent. 81.20 Potash.. 0.42 Soda 0.31 0.55 Lime.. 0.40 Magnesia.. Irou oxide.. 3.41 Alumilla,. 5.84 Phosphoric anhydride. 0.23 Sulphuric . . . . . . . . . . . . 0.08
....................... .......................... ........................ .................... ................... ..................... .........
Nitric acid.
83.45 0.30 0.28
0.30 0.32 2.97 4.55 0.23 0.08
Total by acid. fusion methods. &,45 72.45 0.52 1.75 0.40 0.50 0.53 0.86 0.52 0.72 3.57 3.63 6.88 12.71 0.26 0.28
Sulphuric
0.10
0. I O
NEW BOOKS. A TREATISE ON INDUSTRIAL PHOTOMETRY, WITH SPECIALAPPLICATION TO ELECTRIC LIGHTING. B Y A. PALAZ,PROFESSOR O F INDUSTRIAL ELECTRICITY I N THE S C I E N C E FACULTY O F THE UNIVERSITY O F L A U SANNE. TRANSLATIOX BY GEO. w. PATTERSON, JR., ASSISTANTPROFESSOR O F PHYSICS I N THE UNIVERSITY O F MICHIGAN,ANI) M. R. PATTERSON.pp. 322. New York : D. Van Nostrand Co., 1894. Price, 84.00.
Many of the methods of photometry which have been long in use for measuring the intensity of light from gas flames have required modification when applied to the measurement of the intense light produced by electricity. A book which gathers together and arranges, systematically, the work on the subject which is scattered in many different journals, and which is frequently difficult of access, will be very welcome to many who are interested in the subject. T h e first part of the book gives a discussion of the general principles of photometry and includes a description of all of the common photometers and photometric standards. This part of the book is quite full and will be of value to anyone interested in photometry in any of its applications. Then follow chapters on the equipment of photometric laboratories, and on the measurement of the intensity and distribution of light from electrical sources.
